xdiff: give up scanning similar lines early
[git] / builtin-rerere.c
1 #include "builtin.h"
2 #include "cache.h"
3 #include "string-list.h"
4 #include "rerere.h"
5 #include "xdiff/xdiff.h"
6 #include "xdiff-interface.h"
7
8 static const char git_rerere_usage[] =
9 "git rerere [clear | status | diff | gc]";
10
11 /* these values are days */
12 static int cutoff_noresolve = 15;
13 static int cutoff_resolve = 60;
14
15 static const char *rr_path(const char *name, const char *file)
16 {
17         return git_path("rr-cache/%s/%s", name, file);
18 }
19
20 static time_t rerere_created_at(const char *name)
21 {
22         struct stat st;
23         return stat(rr_path(name, "preimage"), &st) ? (time_t) 0 : st.st_mtime;
24 }
25
26 static int has_resolution(const char *name)
27 {
28         struct stat st;
29         return !stat(rr_path(name, "postimage"), &st);
30 }
31
32 static void unlink_rr_item(const char *name)
33 {
34         unlink(rr_path(name, "thisimage"));
35         unlink(rr_path(name, "preimage"));
36         unlink(rr_path(name, "postimage"));
37         rmdir(git_path("rr-cache/%s", name));
38 }
39
40 static int git_rerere_gc_config(const char *var, const char *value, void *cb)
41 {
42         if (!strcmp(var, "gc.rerereresolved"))
43                 cutoff_resolve = git_config_int(var, value);
44         else if (!strcmp(var, "gc.rerereunresolved"))
45                 cutoff_noresolve = git_config_int(var, value);
46         else
47                 return git_default_config(var, value, cb);
48         return 0;
49 }
50
51 static void garbage_collect(struct string_list *rr)
52 {
53         struct string_list to_remove = { NULL, 0, 0, 1 };
54         DIR *dir;
55         struct dirent *e;
56         int i, cutoff;
57         time_t now = time(NULL), then;
58
59         git_config(git_rerere_gc_config, NULL);
60         dir = opendir(git_path("rr-cache"));
61         while ((e = readdir(dir))) {
62                 const char *name = e->d_name;
63                 if (name[0] == '.' &&
64                     (name[1] == '\0' || (name[1] == '.' && name[2] == '\0')))
65                         continue;
66                 then = rerere_created_at(name);
67                 if (!then)
68                         continue;
69                 cutoff = (has_resolution(name)
70                           ? cutoff_resolve : cutoff_noresolve);
71                 if (then < now - cutoff * 86400)
72                         string_list_append(name, &to_remove);
73         }
74         for (i = 0; i < to_remove.nr; i++)
75                 unlink_rr_item(to_remove.items[i].string);
76         string_list_clear(&to_remove, 0);
77 }
78
79 static int outf(void *dummy, mmbuffer_t *ptr, int nbuf)
80 {
81         int i;
82         for (i = 0; i < nbuf; i++)
83                 if (write_in_full(1, ptr[i].ptr, ptr[i].size) != ptr[i].size)
84                         return -1;
85         return 0;
86 }
87
88 static int diff_two(const char *file1, const char *label1,
89                 const char *file2, const char *label2)
90 {
91         xpparam_t xpp;
92         xdemitconf_t xecfg;
93         xdemitcb_t ecb;
94         mmfile_t minus, plus;
95
96         if (read_mmfile(&minus, file1) || read_mmfile(&plus, file2))
97                 return 1;
98
99         printf("--- a/%s\n+++ b/%s\n", label1, label2);
100         fflush(stdout);
101         xpp.flags = XDF_NEED_MINIMAL;
102         memset(&xecfg, 0, sizeof(xecfg));
103         xecfg.ctxlen = 3;
104         ecb.outf = outf;
105         xdi_diff(&minus, &plus, &xpp, &xecfg, &ecb);
106
107         free(minus.ptr);
108         free(plus.ptr);
109         return 0;
110 }
111
112 int cmd_rerere(int argc, const char **argv, const char *prefix)
113 {
114         struct string_list merge_rr = { NULL, 0, 0, 1 };
115         int i, fd;
116
117         if (argc < 2)
118                 return rerere();
119
120         fd = setup_rerere(&merge_rr);
121         if (fd < 0)
122                 return 0;
123
124         if (!strcmp(argv[1], "clear")) {
125                 for (i = 0; i < merge_rr.nr; i++) {
126                         const char *name = (const char *)merge_rr.items[i].util;
127                         if (!has_resolution(name))
128                                 unlink_rr_item(name);
129                 }
130                 unlink(git_path("rr-cache/MERGE_RR"));
131         } else if (!strcmp(argv[1], "gc"))
132                 garbage_collect(&merge_rr);
133         else if (!strcmp(argv[1], "status"))
134                 for (i = 0; i < merge_rr.nr; i++)
135                         printf("%s\n", merge_rr.items[i].string);
136         else if (!strcmp(argv[1], "diff"))
137                 for (i = 0; i < merge_rr.nr; i++) {
138                         const char *path = merge_rr.items[i].string;
139                         const char *name = (const char *)merge_rr.items[i].util;
140                         diff_two(rr_path(name, "preimage"), path, path, path);
141                 }
142         else
143                 usage(git_rerere_usage);
144
145         string_list_clear(&merge_rr, 1);
146         return 0;
147 }